The introduction of polyester/cotton permanent press fabrics in the 1960's was an immediate marketing success that also brought significant challenges to the fabric industry. In the textile industry, size materials are typically applied to yarns, prior to weaving, to strengthen the yarn and reduce breakage during the weaving process. For permanent press fabrics, conventional starch based warp sizes developed for cotton were incompatible with polyester fiber and would not adhere to the warp yarn. Abrasive forces developed by the loom quickly destroyed the warp yarn, resulting in a weaving industry that could not meet the growing demand.
Size suppliers began evaluating polyvinyl alcohol (PVA) as a primary film former in their formulations. PVA forms a strong film around the outside of the yarn and does not rely on adhesion to the fiber bundle to provide abrasion resistance. PVA was an answer to the problem and was quickly adopted by the industry. While PVA based compositions cannot access the interior areas of yarn bundles, these compositions became the industry standard despite persisting low yarn quality issues.
Other materials, such as colloidal silica, have been explored for use in sizing compositions, but the abrasive nature of such materials resulted in undesirable wear on manufacturing equipment. More recently, efforts to encapsulate colloidal silica particles with a protective barrier were explored using low molecular weight polyester resins. The resulting encapsulated colloidal silica complex could then be added to a conventional PVA/starch size formulation. The two component system could be formed rapidly, but was only stable for short periods of time before the colloidal silica escaped from the protective barrier, resulting in gelling and rapid agglomeration. Efforts to stabilize the two component system using polyglycols were also attempted with limited success. While the polyglycol stabilized formulations improved woolen yarn production and reduced fiber shed in knitting package dyed cotton yarn, the formulations did not provide significant improvement in weaving performance.
Accordingly, there remains a need in the fabric industry for compositions and methods to enhance fiber cohesion. This need and other needs are satisfied by the various aspects of the present disclosure.